Control of lipoprotein lipase secretion by macrophages: effect of macrophage differentiation agents.
The effect of macrophage differentiation agents on lipoprotein lipase (LPL) secretion by macrophages at different stages of differentiation/maturation was investigated. Phorbol myristate acetate (TPA) had an augmenting effect on LPL secretion by in vitro-derived bone marrow macrophages (BMMs), thioglycollate-elicited peritoneal macrophages (TgM phi), and resistant macrophages. Augmentation was time dependent and reached approximately two-fold and approximately threefold increase over control cells within 16 and 96 hr, respectively. TPA did not affect LPL secretion from J774.1 cells treated with the agent for 16-72 hr. L-cell conditioned medium (L-CM), a source of macrophage colony-stimulating activity, augmented LPL secretion by BMMs and Tg-M phi, and when added together with TPA had an additive augmenting effect on LPL secretion in these cells. Retinoic acid (RA) exerted a time-dependent suppressive effect on LPL secretion by BMMs (46% within 16 hr and 83% within 6 d), had a relatively small effect on secretion from J774.1 cells (approximately 20% in 72 hr) and had no effect on LPL secretion by Tg-M phi. Dexamethasone suppressed LPL secretion by BMMs, Tg-M phi, and J774.1 cells. Optimal suppression of LPL secretion by BMMs required more than 24 hr. Thus, TPA and L-CM, agents that exert a mitogenic effect on BMMs and Tg-M phi, augmented the secretion of LPL in these cell types, and RA and dexamethasone, agents which induce differentiation patterns in myeloid cells, suppressed LPL secretion.
Goldman
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Department of Membrane Research, Weizmann Institute of Science, Rehovot, Israel.
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D003907:Dexamethasone / Q000494:pharmacology; D008071:Lipoprotein Lipase / Q000378:metabolism*; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014212:Tretinoin / Q000494:pharmacology
D014212:Tretinoin; D003907:Dexamethasone; D008071:Lipoprotein Lipase; D013755:Tetradecanoylphorbol Acetate